1. Field of the Invention
The invention relates generally to mine surveillance systems and, more particularly, but not by way of limitation, it relates to a permanent form of installation for detecting and processing seismic data indicative of disturbances in and around an underground mine.
2. Description of the Prior Art
Various attempts to derive meaningful subterranean information relative to mine activity or emergency location needs are present in the prior art. There have been devised many forms of electrically actuated indicator apparatus for conveying a particular condition from an underground mine location to a surface station thereby to provide alarm or warning when necessitated. Such systems, however, have been limited to an actively operable transmission type of link, whether by electric wire, radio wave propagation or voice tube. Still other teachings have long dwelled on the possibility of some form of sound locating apparatus wherein acoustic energy is surface-detected to derive either message information or underground location information, but in general such devices have been rudimentary in nature and deployed in non-uniform, unique manner for each given instance. The closest prior art known to Applicants is U.S. Pat. No. 3,132,330 in the name of Donner entitled "Electric Alarm Systems". This system utilizes a plurality of ground-disposed geophones for detecting subsurface disturbances which are individually connected to a particular alarm device characteristic of a surface position. Also to be included in the prior art must be the U.S. Patent application Ser. No. 423,279 as filed on Dec. 10, 1973 entitled "Underground Mine Surveillance system" and assigned to the present assignee now abandoned in favor of application Ser. No. 589,569, filed June 23, 1975, and issued as U.S. Pat. No. 3,949,353 on Apr. 6, 1976.